Australian patent AU2003245113 (UHS Systems Pty Ltd) discloses a customer terminal adapted to be inserted between a burglar alarm system (panel) and a communication network. The customer terminal, on the side connected to the burglar alarm system, emulates the burglar alarm system communication protocol, such as a standard PSTN interface for the burglar alarm system, while sending and receiving messages on its network side in a format compatible with IP and cellular networks. This enables the burglar alarm system to communicate via the customer terminal with a communication network using a different communication protocol from that of the burglar alarm system. For example, such a customer terminal can be adapted to enable a burglar alarm system restricted to communicating via the PSTN to interface with a TCP/IP communication network.
Many burglar alarm systems currently in operation are designed to communicate via the public switched telephone network (PSTN) as shown in FIG. 1. The burglar alarm system (1.101) is connected to the incoming telephone line (1.103) which it uses to send alarm events via the PSTN (1.104) to a known dialer receiver (1.106), which is also connected to the PSTN via a telephone line (1.105). The telephone set (1.102) is generally connected in way that allows it to be disconnected in the event that the burglar alarm system (1.101) has an alarm to send via the PSTN (1.104).
The dialer receiver (1.106) is adapted to terminate the phone call from the burglar alarm system (1.101) and to receive and decode the message from the burglar alarm system (1.101), which is encoded in a known voice frequency format such as ContactID or SIA (Security Industry Association) format. On correctly decoding the message, the dialer receiver (1.106) returns a voice frequency encoded acknowledgement signal to the burglar alarm system (1.101) and sends the decoded alarm message to an automation system computer program (1.108) located at the central monitoring station, the automation system organising the display of the alarm messages to a human operator at the central station. The connection (1.107) between the dialer receiver (1.106) and the automation system (1.108) can be via a serial data connection, Ethernet and the like.
It can be seen from the above that the burglar alarm systems use a telecommunications network and a receiver to send alerts to be displayed on an automation system used by an operator.
With the widespread roll out of IP networks (FIG. 2), various burglar alarm system manufacturers have introduced IP mediation devices (2.020) which enable the transmission of alarm signals from a locally connected burglar alarm system (2.101) over IP networks (2.026) to IP enabled dialer receivers (2.030) where the destination IP address of the IP dialer receiver (2.030) can be programmed into the IP mediation devices (2.020).
These IP mediation devices (2.020) are either generic, converting the alarm signals from the PSTN interface (2.022) of a burglar alarm system (2.101) to IP (2.024) or proprietary format—supporting connectivity to burglar alarm system (2.101) from the specific manufacturer using an internal interface (2.022) which may be serial (e.g. RS.232 and the like) or various forms of keypad bus implementation, RS.485 or a proprietary interface. The burglar alarm system can be a third party system made by a different manufacturer from the manufacturer of the mediation device. Generally the manufacturer of the mediation device (2.020) is also the manufacturer of the IP enabled dialer receiver (2.030) located at the central station.
FIG. 3 shows that the mediation device (3.020) can also use a wireless connection, such as WiFi or cellular (3.024) to communicate alarm signals via the IP network (3.026) to the IP enabled dialer receiver unit (3.030) located at the central station.
The increasing popularity of cellular and broadband (IP) networks has resulted in more and more people cancelling their PSTN lines. This trend has driven the need to introduce PSTN replacement solutions for the delivery of alarm signals from customer premises to the various central stations. One such solution is shown in FIG. 4 where a range of burglar alarm systems (4.101) are communicating with a range of central station automation systems (4.108, 4.060) via customer terminal units (4.040, 4.042, 4.044). A management terminal 4.046 mediates between the remote devices and the automation systems at the central stations.
Each customer terminal unit (4.040, 4.042 and 4.044) connects to an associated burglar alarm system (eg, 4.101) via an interface (4.022) which may be one of: Dial Capture (FXS (Foreign Exchange Subscriber)), serial, RS.485 proprietary keypad bus or parallel inputs (PINs). Customer terminal units (4.040, 4.042 and 4.044) convert the alarm event signals sent by the burglar alarm systems (4.101) into a form compatible with wired (4.041) or wireless (4.404) IP networks. Customer terminal 4.044 is shown as being adapted for both wired and wireless communication providing path redundancy. The customer terminals address messages to the management terminal via the IP network. The signal traverses the IP network (4.026) to reach the management server (4.046), which can be connected to the IP network (4.026) via duplicated data links (4.048) to provide back-up. The management terminal (4.046), which may also be duplicated, can be a server which delivers the alarm signal to the destination central station automation system (4.108) via the IP network (4.026). In order to complete the delivery of the alarm event message to the automation system (4.108), the alarm event has to be delivered in a manner compatible with the automation system. In FIG. 4 this is achieved using agency terminal units (4.050, 4.052) that are adapted to convert the lP signal into an IP or serial form compatible with the automation system that connect to the IP network (4.026) via single (4.047) or redundant (4.049) data links. The agency terminal units (4.050, 4.052) convert the lP signal into an IP or serial form (4.054, 4.056 and 4.058) compatible with the automation system (4.108, 4.060). This method has the disadvantage of requiring the installation of one or more agency terminal units (4.050, 4.052) in every central station (4.000.1, 4.000.2, 4.000.3) which is connected to the IP Network (4.026) used for the alarm delivery network.
Another way of delivering the alarm event messages to the central station automation system is shown in FIG. 5. The network shown in FIG. 5 includes wired and wireless lP devices, 5.040, 5.042, 5.044, adapted for the delivery of alarm event signals from a plurality of burglar alarm systems and a PSTN redialer 5.062 used to convert the alarm event messages from a form compatible with IP networks to one capable of being delivered over the PSTN 5.104 to dialer receiver equipment 5.106 at a plurality of central stations, each equipped with an automation system 5.108. The redialer (5.062) is connected both to the PSTN 5.104 via a POTS line (5.064) and to the IP network (5.026) via data link (5.061). Alarm event messages received from the IP Network (5.026) are converted by the redialer (5.062) to a signal using the known voice frequency based signalling schemes such as ContactID and SIA which are transmitted via the PSTN (5.104) to a known dialer receiver (5.106) also connected to the PSTN via line (5.066). The dialer receiver (5.106) then delivers the alarm event message via a serial or IP interface (5.063) to the automation system (5.108) using a known protocol such as Ademco685. While this scheme is universal in nature, it suffers from a number of disadvantages, including: slowness of alarm delivery, inability to monitor the alarm delivery path and the need by the Central Station operators to retain their PSTN services which can be severed.
In a typical system there may be more than one redialer (5.062) which can be managed as a pool supporting the delivery of alarms over the PSTN (5.104) to multiple dialer receivers (5.106) at multiple central stations. The Management Terminal (5.046) selects the next available redialer (5.062) and sends it a message (FIG. 14) over the IP network (5.046) identifying the phone number of the destination dialer receiver (5.106) and the alarm message to be delivered.
The redialer (5.062) extracts the phone number of the destination dialer receiver (5.106) from the Management Terminal (5.046) message, which is either programmed into the Management Terminal (5.046) or obtained by the Customer Terminal (5.040) from the burglar alarm system (5.101) and attempts to send the event message as per the nominated Format to the destination Dialer Receiver (5.106). The redialer (5.062) responds to the Management Terminal (5.046) with an acknowledgement message (FIG. 15) containing the information in Table 1 allowing the Management Terminal (5.046) to determine whether the message was successfully delivered to its destination.
TABLE 1Response sent by the redialer (5.062) to the Management Terminal (5.046)NAK - Sent immediately on receiving a badly formed alarm packetACK - Sent immediately valid kissoff is received from the Dialer Receiver (5.108)NAK - Sent immediately on no dialtone on the PSTN line (5.064)NAK - Sent on no handshake or no answer timeout on the PSTN line (5.064)NAK - Sent on no kissoff timeout on the PSTN line (5.064)